The interoperability of standard .NET and COM software architectures is achieved using translation tools that reside over legacy COM libraries. The translation tools are run at design time. An example of a translation tool is TLBIMP. These design tools will generate an assembly containing the runtime callable wrapper (RCW) and COM callable wrapper (CCW) classes. A runtime callable wrapper (RCW) which allows a .NET object to call a COM object, and a COM callable wrapper (CCW) allows a COM to output to a .NET object.
During runtime application software will call the RCW and CCW classes directly.
However, many large businesses, for example financial institutions, have equipment that runs proprietary variants of the .NET and/or COM architectures. The output of the standard translation tools referred to above does not provide interface definitions suitable for interfacing with these proprietary architectures. In particular, the generation of .NET interfaces from COM components leads to interface definitions that are unsuitable for interfacing with proprietary .NET interfaces used by financial institutions. This difficulty in interoperability restricts the availability of legacy COM component libraries into systems operating proprietary .NET architectures.
Additionally, interface definitions generated using a standard translation tool contain fields and data that is not associated with a proprietary interface, these interface definitions appear confusing to a user having a detailed knowledge of the proprietary architecture.